Abstract: Methods, compositions, and systems for detecting gamma radiation is disclosed and described. A compound for detecting gamma radiation can comprise a conjugated imidazole having the following structure: [Formula I] where at least one of R1, R2, and R3 are conjugated organic groups. Additionally, the conjugated imidazole can be capable of reacting with a radical or ion formed by the reaction of gamma radiation with a radical generating component such as a halogen solvent to decrease a molar extinction coefficient of the conjugated imidazole in the visible light region or to quench fluorescence of the conjugated imidazole. As a sensor (100), a radiation detection indicator (108) can indicate the change in molar extinction coefficient or fluorescence of the conjugated imidazole material (120) upon exposure to gamma radiation.

Abstract: A fluorescence-based sensor can comprise a nanofiber mass of nanofibers having tubular morphology and a fluorescence detector, where fluorescence of the nanofibers decreases upon contact with a nitro-containing compound. The nanofibers can comprise carbazole-cornered, arylene-ethynylene tetracyclic macromolecules of formula I: where R1-R4 are alkyl-containing groups. The tubular morphology allows for highly selective detection of trinitrotoluene over other nitro-based compounds and oxidizing organic compounds.

Abstract: A photoconductive sensor compound for detecting explosives can have a structure I: where R is a morphology control group, A is a linking group, B is a electron donor that is selective for transferring electrons to PTCDI backbone upon irradiation to make the resulting nanostructures conductive, and R1 through R8 are side groups.

Abstract: A muitimode gas sensor platform (100) can comprise an array of electrode pairs (108) oriented on a substrate (102) and a plurality of detection zones (104), wherein at least a portion of individual electrode pairs (106) are separately addressable. Each detection zone (104) can comprise at least one set of individual electrode pairs (106) within the array, where the individual electrode pairs (106) have organic nanofibers (108) uniformly deposited thereon. The organic nanofibers (108) can be responsive to association with a corresponding target material and at least one detection zone (104) can be electronically responsive to the corresponding target material.

Abstract: A fluorescence based sensor (10) is disclosed and described. The sensor (10) can include nanofibril materials (12) fabricated from a linear carbazole oligomer and a fluorescence detector (14). The linear carbazole oligomer can have the formula (I) wherein n is 3 to 9, R are independently selected amine sidegroups, and at least one, but not all, R is a C1 to C14 alkyl. The carbazole-based fluorescence based sensors (10) can be particularly suitable for detection of explosives and volatile nitro compounds.

Abstract: The present disclosure provides methods and compositions for an organic nanofiber-based heterojunction material, comprising nano fibers of an acceptor molecule, the nano fibers coated with a donor molecule, where the acceptor molecule contains a group and the donor molecule contains a companion group, wherein the group and companion group enables strong binding between the acceptor molecule and donor molecule, the strong binding providing for efficient forward electron transfer between the acceptor molecule and donor molecule, and wherein the group and companion group minimize charge carrier recombination between the acceptor molecule and the donor molecule.

Abstract: A coaxial molecular stack (10) for transferring photocurrent generation in a device such as a solar cell (14) is disclosed. The device comprises a plurality of macrocyclic ?-conjugated planar molecules stackable through columnar self assembly to form a stack (10) having an axial channel (26) with an outer p-channel (22) of the nano-composite coaxial molecular stack (10). A plurality of C60 molecules are positioned coaxially within the axial channel of the stack (10) to form an inner n-channel (24) that forms a bulk heterojunction with the p-channel (22) to provide charge transport of photocurrent through the nano-composite coaxial molecular stack (10). A plurality of the stacks (16) are oriented orthogonally between first (18) and second electrodes (20) to form the device (14).

Abstract: A chemical sensor can include a nanofiber mass of p-type nanofibers having a HOMO level greater than ?5.0 eV. Additionally, the chemical sensor can include oxygen in contact with the p-type nanofibers. Further, the chemical sensor can include a pair of electrodes in electrical contact across the nanofiber mass, where the p-type nanofibers conduct an electric current that decreases upon contact with an amine compound.

Abstract: A sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines. The sensory material is a perylene-3,4,9,10-tetracarboxyl compound having amine binding groups and the following formula where A and A? are independently chosen from N—R1, N—R2, and O such that both A and A? are not O, and R1 through R10 are amine binding moieties, solubility enhancing groups, or hydrogen such that at least one of R1 through R10 is an amine binding moiety. This perylene compound can be formed into well-defined nanofibers. Upon deposition onto a substrate, the entangled nanofibers form a meshlike, highly porous film, which enables expedient diffusion of gaseous analyte molecules within the film matrix, leading to a milliseconds response for vapor sensing.

Abstract: A fluorescence based sensor (10) is disclosed and described. The sensor (10) can include nanofibril materials (12) fabricated from a linear carbazole oligomer and a fluorescence detector (14). The linear carbazole oligomer can have the formula (I) where n is 3 to 9, Rn are independently selected amine sidegroups, and at least one Rn is a C1 to C14 alkyl. The carbazole-based fluorescence based sensors (10) can be particularly suitable for detection of explosives and volatile nitro compounds.

Abstract: A chemical sensor can comprise a nanofiber mass of p-type nanofibers having a HOMO level greater than ?5.0 eV. Additionally, the chemical sensor can comprise oxygen in contact with the p-type nanofibers. Further, the chemical sensor can comprise a pair of electrodes in electrical contact across the nanofiber mass, where the p-type nanofibers conduct an electric current that decreases upon contact with an amine compound.

Abstract: A fluorescence sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines. The sensory material is a perylene-3,4,9,10-tetracarboxyl compound having amine binding groups and the following formula where A and A? are independently chosen from N—R1, N—R2, and O such that both A and A? are not O, and R1 through R10 are amine binding moieties, solubility enhancing groups, or hydrogen such that at least one of R1 through R10 is an amine binding moiety. This perylene compound can optionally be formed into well-defined nanofibers. Upon deposition onto a substrate, the entangled nanofibers form a meshlike, highly porous film, which enables expedient diffusion of gaseous analyte molecules within the film matrix, leading to a milliseconds response for vapor sensing.

Abstract: Methods, compositions, and systems for detecting explosives is disclosed and described. A sensor for detecting explosives can comprise a porous hydrophilic material modified with a titanium oxo compound having the following structure (I) where L is a ligand. Additionally, the porous hydrophilic material can be capable of detecting hydrogen peroxide vapor by complexing the titanium oxo compound and the hydrogen peroxide to provide a color change.

Abstract: A photoconductive sensor compound for detecting explosives can have a structure I: where R is a morphology control group, A is a linking group, B is a electron donor that is selective for transferring electrons to PTCDI backbone upon irradiation to make the resulting nanostructures conductive, and R1 through R8 are side groups.

Abstract: A class of fluorescent, organic nanofibrils, and particularly the films comprising entangled piling of these nanofibrils exhibiting effective quenching of their fluorescence upon exposure the vapor of explosives is disclosed. A sensor and a method for sensing the explosives vapor and other volatile organic compounds is disclosed, including the explosives taggants through the modulation of the fluorescence of the nanofibril film and the electrical conductivity of the nanofibrils. A development of synthetic methods is disclosed, such as protocols and techniques that lead to the production of various arylene-ethynylene macrocycle (AEM) molecules, which consist of a shape-persistent, toroidal scaffold in planar conformation, with minimal ring strain and highly tunable ring sizes (from 0.5 nm to above 10 nm).

Abstract: A coaxial molecular stack (10) for transferring photocurrent generation in a device such as a solar cell (14) is disclosed. The device comprises a plurality of macrocyclic ?-conjugated planar molecules stackable through columnar self assembly to form a stack (10) having an axial channel (26) with an outer p-channel (22) of the nano-composite coaxial molecular stack (10). A plurality of C60 molecules are positioned coaxially within the axial channel of the stack (10) to form an inner n-channel (24) that forms a bulk heterojunction with the p-channel (22) to provide charge transport of photocurrent through the nano-composite coaxial molecular stack (10). A plurality of the stacks (16) are oriented orthogonally between first (18) and second electrodes (20) to form the device (14).

Abstract: A photovoltaic device (10) having a coaxial molecular stack (12) for transferring photocurrent is disclosed. The device (10) comprises a plurality of coaxial molecular stacks (12) located between and oriented substantially perpendicular to first (14) and second (16) electrodes to provide charge transport of photocurrent through each coaxial molecular stack (12) in the photovoltaic device (10). Each coaxial molecular stack (12) comprises a plurality of ?-conjugated planar supramolecules (18) stackable through columnar self assembly to form the coaxial molecular stack (12). Each supramolecule (18) is comprised of a ?-conjugated hub (20) covalently appended to multiple copies of an electron acceptor spoke (22) to form an outer n-channel with a coaxial inner p-channel.

Abstract: The present invention relates to a class of fluorescent, organic nanofibrils, and particularly the films comprising entangled piling of these nanofibrils exhibiting effective quenching of their fluorescence upon exposure the vapor of explosives. The invention also relates to a sensor and a method for sensing the explosives vapor and other volatile organic compounds, including the explosives taggants through the modulation of the fluorescence of the nanofibril film and the electrical conductivity of the nanofibrils. The invention also relates to a development of synthetic methods, protocols and techniques that leads to production of various arylene-ethynylene macrocycle (AEM) molecules, which consist of a shape-persistent, toroidal scaffold in planar conformation, with minimal ring strain and highly tunable ring sizes (from 0.5 nm to above 10 nm).

Abstract: A fluorescent sensor compound based on a perylene core is described and disclosed. The fluorescent sensor compound for detecting mercury can have a structure I: where A and A? are linking groups, B and B? are binding ligands which are selective for binding with Hg2+, and R1 through R8 are side groups. These fluorescence sensor materials are robust against photobleaching, while still providing exceptional detection sensitivity and selectivity.

Abstract: A fluorescence sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines. The sensory material is a perylene-3,4,9,10-tetracarboxyl compound having amine binding groups and the following formula where A and A? are independently chosen from N—R1, N—R2, and O such that both A and A? are not O, and R1 through R10 are amine binding moieties, solubility enhancing groups, or hydrogen such that at least one of R1 through R10 is an amine binding moiety. This perylene compound can optionally be formed into well-defined nanofibers. Upon deposition onto a substrate, the entangled nanofibers form a meshlike, highly porous film, which enables expedient diffusion of gaseous analyte molecules within the film matrix, leading to a milliseconds response for vapor sensing.